关键词: 刚玉浇注料, 抗热震性, SiO₂微粉, 高温液相

Abstract: In order to improve the thermal shock resistance of corundum castables for snorkels of RH furnaces,SiO₂ fume was added with different additions (0,0.1%,0.2%,0.3%,and 0.4%,by mass).The actual working condition was simulated,thermal shock was conducted by preheating and then dipping into steel melt,and the influence of the SiO₂ fume addition on the thermal shock resistance of the castables was investigated by XRD,SEM,and FactSage 8.0.The results show that:(1)the SiO₂ fume addition can improve the thermal shock resistance of the corundum castables for RH snorkels;with the SiO₂ fume addition increasing,the modulus of rupture retention ratio of the specimen under steel dipping thermal shock increases first and then decreases,reaching the maximum (60%) with 0.2% SiO₂ fume addition;(2)the mechanism that SiO₂ fume improves the thermal shock resistance of corundum castables for RH snorkels is as follows:after adding SiO₂ fume,the high temperature liquid phases such as nepheline and melilite formed in the matrix can buffer the thermal stress of the specimens caused by thermal shock under the steel dipping condition.

Key words: corundum castables, thermal shock resistance, silica fume, high temperature liquid phase